I think for the vast majority of STR owners your advice holds, that it's not worth the time.

FHA 3-4 units has a self-sufficiency test which can be difficult to pass in higher priced markets where the rent from the other units needs to be greater than or equal to your total housing payment. 

The vast majority of people I've called don't immediately fly off the handle. 

Now our “leadership” at the National Association of Realtors has proven just as feckless and ineffective as the vast majority of its membership.

So look around, interview other STR owners so that you have sufficient information.

In the 90s Dane County had the reputation of being called "Republic of Dane County" among rental owners because their rental laws were so vastly different from most others in the state. 

Hi Rob,If you believe the HELOC will be sufficient for the purchase & rehab, it could make sense to use the HELOC given the interest rate is lower than a hard money. 

As long expectations are managed, either route should be sufficient. 

If I give her a move-out notice with 3-4 weeks in advance, would it be sufficient?

Jim W mentioned he did not care about those buyers and thats fine most agent that work with investors can take that line of thought.. but thats not the majority of transactions in the USA  retail mom pop I want to buy a home to live in makes up the vast majority of transactions.. its going to really hurt the FHA VA  cash strapped buyer ..